PSL/PSA is a computer-aided structured documentation and analysis technique that was developed for, and is being used for, analysis and documentation of requirements and preparation of functional specifications for information processing systems. The present status of requirements definition is outlined as the basis for describing the problem which PSL/PSA is intended to solve. The basic concepts of the Problem Statement Language are introduced and the content and use of a number of standard reports that can be produced by the Problem Statement Analyzer are briefly described.